Cook cabbage, uncovered in boiling salt water for 5 minutes. Rinse under cold running water until cool; drain, pressing out all liquid with your hands. Place the cabbage in a large bowl. Combine eggs, egg yolk, milk, flour, melted butter, and salt (in that order) in a blender container. Blend until smooth. Combine this mixture with the cabbage in the bowl; stir in the chives or scallions. Melt 1 tablespoon butter in a large heavy skillet over medium heat. Spoon the batter, 1 large tablespoon for each pancake, into the skillet. Cook three or four at a time until golden on both sides. Keep warm in a low oven while frying the remaining batter, adding more butter to the skillet as needed.